This book provides a comprehensive exploration of reliability, maintainability, and maintenance management, essential concepts for ensuring the long-term quality and functionality of products in today's dynamic market. It traces the evolution of maintenance from reactive to Maintenance 4.0, integrating cutting-edge technologies such as IoT, AI, and digital twins to optimize asset health. Each chapter delves into key elements-reliability engineering, systems reliability, and condition monitoring-building a foundation for predictive maintenance. Emerging trends, including autonomous systems and augmented reality, are examined as the future of maintenance. Aimed at students, professionals, and manufacturers, this book offers insights and practical guidance for mastering advanced maintenance strategies.